IE44857B1

IE44857B1 - New 7-aminothiazolylacetamido-cephalosporanic acid derivatives,processes for preparing them and pharmaceutical compositions containing them

Info

Publication number: IE44857B1
Application number: IE76/77A
Authority: IE
Original assignee: Roussel Uclaf
Priority date: 1976-01-14
Filing date: 1977-01-14
Publication date: 1982-04-21
Also published as: BE850338A; CH617204A5; FR2342733A1; DK12477A; GB1543004A; ES454997A1; CA1094546A; SE434842B; SE7613990L; JPS6337116B2; CH621555A5; DE2700552C2; US4097595A; GB1543005A; JPS59144785A; IE44857L; DK153489C; NL7700406A; JPS5287192A; LU76566A1

Abstract

Novel 7-amino-thiazolyl-acetamido-cephalosporanic acid compounds of the formula I wherein R is selected from the group consisting of hydrogen and a group easily removable by acid hydrolysis or hydrogenolysis, R1 is selected from the group consisting of alkyl of 1 to 4 carbon atoms, a 5 member heterocyclic ring and a 5 member heterocyclic ring containing a ketone group and A is selected from the group consisting of hydrogen, alkali metal and equivalents of alkaline earth metals, magnesium and organic amine having antibiotic activity against gram negative and gram positive bacteria and their preparation and novel intermediates therefore.

Description

This invention relates to 7 - aminothiazolylacetamido cephalosporanic acid derivatives, processes for preparing them and pharmaceutical compositions containing them. More particularly this invention relates to 7 - aminothiazolylacetamido - cephalosporanic acid derivatives displaying antibiotic activity.

Accordingly, in one of its aspects, this invention provides the 7- aminothiazolylacetamido - cephalosporanic acid derivatives of the general formula: /R HN - LJ w wherein R represents either a hydrogen atom or a group removable by - 2 acid hydrolysis or by hydrogenolysis; R-| represents either an alkyl radical having from 1 to 4 carbon atoms or a 5 membered heterocycle optionally containing a carbonyl group as one of its members; and A represents a hydrogen atom, an alkali metal atom, a substituted ammonium group, an equivalent of an alkaline-earth metal atom or an equivalent of a magnesium atom.

The term a group removable by acid hydrolysis or hydrogenolysis is used to mean a group which may be cleaved from the molecule by acid hydrolysis or hydrogenolysis without the structure of the molecule being otherwise affected. By way of example, R may be t - butoxycarbonyl, trityl, benzyl, dibenzyl, trichloroethyl,carbobenzyloxy, formyl or an equivalent of a phthaloyl group.

R1 can be, for example, a methyl, ethyl, propyl, ispropyl, butyl, eeo - butyl, f - butyl, furyl, thiazolyl, oxothiazolinyl (especially the 2 - oxo - (3H) - thiazolin - 4 - yl group), -isothiazolyl, oxazolyl, diazolyl (for instance imidazolyl), thiadiazolyl or tetrazolyl radical.

When it is a metal atom, A preferably represents a so'dium, potassium or lithium atom, or an equivalent of a calcium or magnesium atom, and when it is a substituted ammonium group, A preferably represents a group derived from an amine such as trimethyl amine, tirethylamine, methylamine, propylamine, N,N - dimethylethanolamine or tot's - (hydroxymethyl) - methylamine.

A preferred group of compounds of general formula I are those wherein R represents a ί - butoxycarbonyl, trityl, dibenzyl, tri chloroethyl or carbobenzyloxy group.

A more particularly preferred group of compounds of general formula I are those wherein R represents a hydrogen atom or a trityl group, Rj represents a methyl, ethyl, furyl or 2 - oxo - (3H) - 3 .^3^ thiazolih - 4 - y] radical, and A represents a hydrogen atom. -/2 - (2- amino - 4 - thiazolyl) - acetamido7 - 3 - (acetylthiomsthyl) - ceph - 3 - em -4-carboxylic acid is a particularly preferred compound.

. The compounds of general formula I can exist either in the form set out as hereinbefore or in an isomeric form-as compounds of general, formula:.

R $ N .

S flH wherein R, R-j and A are as defined hereinbefore. It should be under10 stood, therefore, that the term compound of general formula I as used . herein includes both of these isomeric forms within its scope.

In another aspect, this invention provides a first process for preparing certain compounds of general formula I, in which an appropriate compound of general formula: wherein R-j is as defined hereinbefore, is treated with an appropriate acid of general formula: - 4 r>jh (III) or with a functional derivative thereof (wherein R1 represents a group removable by acid hydrolysis or by hydrogenolysis) to obtain the desired product of general formula: HN —r' wherein R1 and R^ are as defined hereinbefore-which product corresponds to a compound of general formula I wherein R does not represent a hydrogen atom and A represents a hydrogen atom.

In a preferred method of performing this process a functional 10 derivative of the acid of formula III is employed. The functional derivative may be an acid chloride or an acid anhydride, the latter conveniently being formed in situ by the action of wobutyl chloroformate on the acid. However, it is possible to use other acid halides, - 5 or anhydrides formed in situ by the action on the acid of other alkyl chloroformates, dialkylcarbodiimides or dicycloalkylearbodiimides such as dicyclohexylcarbodiimide. Other acid derivatives, such as the acid azide, the acid amide, or an acid ester formed, for example, with hydroxysuccinimide, p ~ nitrophenol or 2,4 - dim'trophenol, may also be used.

In a process in which the product of formula II is treated with a halide of the acid of general formula III, or with an anhydride thereof formed with isobutyl chloroformate, the reaction is preferably carried out in the presence of a base. The base may be, for example, an alkali metal carbonate, a tertiary amine such as N - methyl-morpholine or pyridine, or a tri alkyl amine such as triethylamine.

The compounds of general formula II, which are also new, can in turn be prepared by treating an appropriate compound of general formula: R,-C~S-B (IV) Ί (wherein is defined as hereinbefore and B represents an alkali metal atom or hydrogen atom) with 7 - amino - cephalosporanic acid.

B is preferably sodium or potassium and it is also preferred for the preparation to be carried out under an inert atmosphere in the presence of hydroquinone.

The compounds of general formula IV, of which some are new, can in turn be prepared by the action of sodium hydrosulphide on an appropriate acid chloride of general formula R^COCl, (wherein R^ is as defined hereinbefore) employing a method similar to that described in J. Antibiotics 27-8-577 (1974). An example of such a - 6 4 4 8 5 7 preparation is set out hereinafter in the Examples.

The compounds of general formula III may be prepared using standard reactions for the protection of an amine function, as applied to 2 - amino - 4 - thiazolylacetic acid or one of its esters. An example of such a preparation is also set out in the Examples.

Certain other compounds of general formula I may be prepared by a second process in which an appropriate compound of general formula Ia is hydrolysed in an acidic medium, or hydrogenated, to form the corresponding product of general formula: NH„ (wherein R-j is defined as hereinbefore) which product corresponds to a compound of general formula I in which R and A both represent hydrogen atoms.

When R' of general formula Ia is a t - butoxycarbonyl or a 15 trityl group it is advantageous to perform the above reaction by hydrolysis in an acidic medium; the acid employed is preferably trifluoroacetic acid, formic acid or acetic acid, employed either in anhydrous or in aqueous form.

When R' of general formula Ia is a tri chloroethyl group it is 20 advantageous to perform the reaction by hydrogenolysis employing a hydrogenating agent, preferably a zinc/acetic acid system. - 7 When Rr of general formula Ia is a benzyl, dibenzyl or carbobenzyloxy group the reaction is preferably performed by catalytic hydrogenation.

In a further aspect, this invention provides a third process for preparing certain compounds of general formula I in which an appropriate compound of general formula: R\ NH S N CH 02 •CH, (V) (wherein R is as hereinbefore defined and A' represents a hydrogen atom or an alkali metal atom) is treated with an appropriate compound Ίθ of general formula IV to give the corresponding compound of general formula I wherein A represents a group A1- that is to say, either a ' salified or non-salified product of an acid of general formula Ia or general formula lb.

The reaction is preferably performed in water, or in a water/ acetone mixture, but other aqueous solvents, for example water/dioxane, water/tetrahydrofuran or water/ethanol mixtures, may be employed. Also, the reaction is advantageously performed in the presence of a buffer that maintains the pH of the reaction medium close to neutrality, such as a monosodium phosphate/sodium acid carbonate buffer. 2o The compounds of general formula V may be prepared by the action of an appropriate compound of general formula III on 7 - amino - 8 4 4 8 5? cephalosporanic acid followed, if necessary, by acid hydrolysis or hydrogenolysis. An example of these reactions is given in the Examples.

In a preferred form of the third process of the invention B and A' in the compounds, IV and V represent alkali metal atoms, so that the formed compound of general formula I is one in which A represents an alkali metal atom. The corresponding unsalified compound (wherein A represents a hydrogen atom) may be prepared by treatment of this formed compound with an acid. This acid is advantageously acetic acid, but other mineral or organic acids, such as hydrochloric, sulphuric, formic, oxalic or trifluoroacetic acid, may be used.

However, in the case in which a compound of general formula V, wherein A' represents an alkali metal atom and R represents a hydrogen atom, is reacted with a compound of general formula IV, wherein B represents an alkali metal atom, the acetic acid formed during the reaction may permit the desired product of general formula Ib to crystallise out in the form of an internal salt, thus rendering unnecessary the use of acid described above.

The compounds of general formula IV and V in which B and A' respectively represent an alkali metal atom are preferably prepared in situ by salifying the appropriate corresponding compounds of general formulae IV and V in which B and A' respectively represent a hydrogen atom.

The alkali metal atom represented by A' and B is preferably a sodium or potassium atom, so that the salification is preferably performed using sodium Or potassium bicarbonate. Other alkaline reagents, such as sodium or potassium hydroxide or sodium or potassium carbonate may however be used.

Those compounds of general formula I, wherein A represents an alkali metal atom, an equivalent of an alkaline-earth metal atom - 9 or of magnesium, or a substituted ammonium group,'may of course be prepared by treating the corresponding compound of general formula I wherein A represents a hydrogen atom with a suitable base. In the case in which A is to be a metal atom, a mineral base such as a carbonate or hydroxide is conveniently employed. Naturally the appropriate amine is employed to form a desired substituted ammonium salt.

The salification reaction is preferably performed in a solvent, such as water, ethyl ether, ethanol or acetone, or a 1q mixture of these solvents.

The compounds of general formula I are pharmacologically active and may be useful as antibiotics against both Gram-positive bacteria such as the staphylococci, especially penicillin-resistant strains, or the streptococci, and Gram-negative bacteria, especially the coliform bacteria, the proteus or the klebsiellae..

Thus the compounds of general formula I may be suitable for use as medicaments in the treatment of staphylococcal infections such as staphylococcal septicaemia, malignant facial or. skin staphylococcal infections, pyodermatitis, septic or suppurating 2o sores, anthrax, phelgmons, erysipelas, acute primary or postinfluenza staphylococcal infections, bronchopneumonia and pulmonary suppurations; they may also be used as medicaments in the treatment of colibacillosis and associated infections, in infections caused by Proteus and Klebsiella, and in other complaints caused by Gram25 negative bacteria.

Thus, the pharmacologically acceptable compounds of general formula I, especially those mentioned hereinbefore as preferred and those described in the Examples, may be useful in human or veterinary medicine, particularly when applied as antibiotic medicaments. - 10 4 *85 However, before any of the compounds of this invention may be used in medicine, they should preferably be formed into pharmaceutical compositions by association with suitable pharmaceutical vehicles.

The term pharmaceutical is used herein to exclude any 5 possibility that the nature of the vehicle, considered of course, in relation to the route by which the composition is intended to be administered, could be harmful rather than beneficial.

The choice of a suitable mode of presentation, together with an appropriate vehicle, is believed to be within the competence of those accustomed to the preparation of pharmaceutical formulations.

Accordingly, in yet another aspect, this invention provides pharmaceutical compositions containing one or more compounds of general formula I, in association with a suitable pharmaceutical vehicle.

The compositions of this invention may be administered bucally, rectally or parenterally, or by the local route by topical application to the skin and mucous membranes, and in respect ofthese modes, the pharmaceutical vehicle is preferably:a) the ingestibie excipient of a tablet, coated tablet, sublingual tablet or pill; the ingestibie container or a capsule or cachet; the ingestibie pulverulent solid carrier or a powder or granules; or the ingestibie liquid (aqueous or non-aqueous) medium of a syrup, solution, suspension or elixir, b) the solid or liquid medium of a paste, lotion, cream, gel or unguent, c) a sterile injectable liquid solution or suspension medium, or d) a base material of low melting point capable of releasing the active ingredient to perform its pharmacological function, which base material when appropriately shaped - 11 4dSOftU'iHi a kuppi&l hit \, Whilst the modes of presentation just listed represent those most likely to be employed, they do not necessarily exhaust the possibilities.

The materials employed as vehicles may be talc, gum arabic, lactose, starch, magnesium stearate, fatty substances of animal or vegetable origin such as, paraffin derivatives and especially glycols or cocoa butter, optionally compounded with one or more wetting, dispersing or emulsifying agents and/or one or more • preservatives.

The compounds of this invention may preferably be administered in the form of plain or sugar-coated compressed tablets, gelatin capsules, granules, suppositories, injectable preparation, ointments, creams and gels.

Whilst the dosage of the pharmacologically active ingredient will vary with the complaint and subject treated, and with the route of administration and the compound administered, it may be said by way of example that for the compound of Example 2 the dosage would be between 0.250 g and 4 g per day when administered by the oral route in man, or between 0.500 g and 1 g, three times a day, when administered by the intramuscular route in man.

The compounds of general formula II are new, as has been mentioned hereinbefore, and those wherein represents an alkyl radical having from 1 to 4 carbon atoms are preferred. The compound 7 - amino - 3 - acetylthiomethyl - ceph - 3 - em - 4 - carboxylic acid is especially preferred.

The compounds of general formula II may be prepared by the method described hereinbefore.

The compounds of general formula II per se and processes for - 12 4 4 8 S 7 and processes for their preparation are described and claimed in our British Patent Specification No. 1543005.

The following Examples are given, though only by way of illustration, to show some preferred aspects of the invention: Example 1 7-/2- (2 - trityl ami no'- 4 - thiazolyl) - acetamido/- 3 - acetylthiomethylceph - 3 - em - 4 - carboxylic acid.

A mixture of 1.63 g of 7 - /2 - (2 - tritylamino - 4 - thiazolyl) acetamido/ - 3 - acetoxymethyl ceph -3-em - 4 - carboxylic acid, 0.21 g of sodium bicarbonate, 0.66 g of potassium thioloacetate, 10 cm of water and 5 cm3 of acetone is brought to 90°C and maintained there 3 for 150 minutes. It is then acidified with 1 cm of acetic acid and vacuum-filtered. The product is washed and purified by chromatography on silica, eluting firstly with a 1:1 methylene chloride - ether mixture, then with a 5:1:4 acetone - water - ether mixture. 830 mg of the expected product were recovered.

The 7 - /7 - (2 - tritylamino - 4 - thiazolyl) - acetamido/ - 3 acetoxymethylceph - 3 - em - 4 - carboxylic acid used at the start of the Example 1 was prepared as follows: Stage A: 2 - tritylamino - 4 - thiazolyl acetic acid: 930 mg of ethyl 2 - amino - 4 - thiazolylacetate, 25 cm of dry chloroform, 0.8 cm of tri ethyl - amine and 1.65 g of trityl chloride are mixed then agitated together for three hours, after which 3 cm of N hydrochloric acid and 5 cm of water were added. The mixture was agitated and decanted before adding 55 cm of N hydrochloric acid and 5 cm of water to the residue, decanting again, then drying and concentrating the remaining residue to dryness. - 13 3 3 cm of dioxane and 6 cm of N sodium hydroxide ware added to the residue and the formed mixture was agitated first at 50°C, then at ambient temperature for one night. The solvent was then driven away and the residue was diluted with water, washed with ether, acidified with 0.5 cm of acetic acid, and allowed to crystallise.

The crystals were separated by vacuum-filtration to give 1.33 g of -the desired 2 -tritylamino - 4 - thiazolyl - acetic acid, which may be purified by pasting with ether.

M.Pt.=220°C, Stage B; 7-/2- (tritylamino - 4 - thiazolyl) - acetamido/ - 3 acetoxymethylceph - 3 - em - 4 - carboxylic acid: 801 mg of 2 - tritylamino - 4 - thiazolyl - acetic acid, 10 cm of dry tetrahydrofuran and 2 cm of a molar solution of N - methyl morpholine in tetrahydrofuran were mixed together with agitation. The formed mixture was cooled to -20°C and 2 cn7 of a molar solution of isobutyl chloroformate in tetrahydrofuran were added with agitation, followed by a solution of 544 mg of 7 - amino - cephalosporanic acid 3 in 24 cm of a molar solution on N - methylmorpholine in tetrahydro3 furan and 10 cm of water; the mixture v;as further agitated and allowed to warm.. The solvent was then eliminated to leave a residue which was 3 diluted with water before the addition of 2 cm of 2N hydrochloric acid. The mixture was vacuum-filtered and the residue was dried. 1.16 g of the expected acid were isolated.

Example 2 7-/2-(2- amino - 4 - thiazolyl) - acetamido/ - 3 - acetyl thi o25 methylceph - 3- em- 4 -carboxylic acid.

The product obtained in Example 1 was dissolved in 50% aqueous formic acid and warmed at 60°C for fifteen minutes. The formic acid - 1.4 44SS? was driven off; the residue was taken up with acetone then vacuumfiltered to give 325 mg of product, which was purified by dissolving 3 it in 2.6 cm of acetone containing 205! of water and 0.3 cm of 2N hydrochloric acid, then vacuum-filtering and adding 3 drops of 3 pyridine and 1 cm of acetone. 0.228 mg of purified product were obtained. C15H16°5N4S3 3% 22.44 S% 20.09 Calculated: C% 42.04 Found: C% 41.7 H% 3.76 N% 13.07 H% 3.9 N% 12.8 10 Example 3 7-/2-(2- tritylamino - 4 - thiazolyl) - acetamido/ - 3 - acetylthiomethy!ceph - 3 - em - 4 - carboxylic acid. 9.9 g of 2 - tritylamino - 4 - thiazolyl - acetic acid, 100 cm of tetrahydrofuran and 2.7 cm of N - methylmorpholine were mixed under an inert atmosphere and agitated for a quarter of an hour at ambient temperature. The mixture was cooled to -15°C and 3.15 cm3 of isobutylchloroformate were added; the mixture was agitated for a further minutes between -10 and -15°C. 6.5 g of 7 - amino - 3 - acetylthiomethy!ceph - 3 - em - 4 3 3 carboxylic acid, 65 cm of water and 3.15 cm of triethylamine were added to the mixture over two minutes; the mixture was agitated for 90 minutes, it being allowed to come back to ambient temperature, and then the tetrahydrofuran was driven off; the residue was acidified, extracted with methylene chloride and vacuum-filtered to isolate the insoluble matter. The organic phase was washed, concentrated, and the powder obtained was triturated with ether and dried to give 15.2 g of crude product. 6.7 g of crude product was purified by dissolving it in methylene - 15 ' cfl ori de, adding ethyl acetate, separating off the insoluble portions, treating the remaining solution with carbon black, vacuum-filtering, then rinsing and drying to give 5'.1 g of expected product.

The 7 - amino - 3 - acetylthiomethylceph - 3 - em - 4 5 carboxylic acid used at the start of Example 3 was prepared as follows·. .44 g of 7 - amino - cephalosporanic acid and 50 cm of water containing 1% of hydroquinone were mixed with agitation under.an inert gas. 1.7 g of sodium bicarbonate were added, followed, after dissolution, by 3 g of potassium - thioloacetate. The mixture was agitated for three hours at 60°C, cooled, then acidified with acetic acid. The mixture was further agitated at ambient temperature then vacuum-filtered; the solid was washed and dried to give 4.9 g of'the desired product.

Example 4 7-/2 - (2 - amino - 4 - thiazolyl) - acetamido/ - 3 - 2((2*oxo-(3H)15 thiazolin - 4- yl) - carbonyl) -thioraethyl/- ceph - 3 - em - 4 carboxylic acid. 0.825 g of 7-/2- (2 -amino - 4 - thiazolyl) - acetamido/ - 3 3 acetoxymethylceph - 3 - em - 4 - carboxylic acid. 4 cm of distilled water, 0.4 g of (2 - oxo - (3H) - thiazolin - 4 - yl) - thiolocarboxylic acid, 0.39 g of monosodium phosphate and 0.21 g of sodium bicarbonate were mixed then agitated for five hours; the mixture was cooled and acetic.acid added until pH of 4 to 5 was reached. The percipitate obtained was vacuum-filtered and dried to give 0.56 g of crude product.

This product was dissolved'in 5 cm of water containing one molar equivalent of sodium bicarbonate and passed through an ion exchange resin, eluting with water; the product was: recovered with water containing 10% of isopropanol. The fractions containing the product were reunited, then acidified with acetic acid. 0.12 g of .-1644857 expected product were obtained. An Ultra Violet spectrum in ethanol containing 10% of hydrochloric acid gave: max. 258 nm ε-16,350; max 307 nm e=10,350.

An Infra Red spectrum in nujol gave: 1772 cmT (β lactam); 1682 to 1638 cnH (C=0, secondary amide ).

The product obtained may also exist in a form isomeric to that named in the title, that is as 7 - /7 - (2 - amino - 4 - thiazolyl) acetamido? - 3 - /_((2-hydroxy - 4 - thiazolyl) carbonyl) - tniomethyl? ~ ceph - 3 - em - 4 - carboxylic acid.

The 7-/7-(2- amino - 4 - thiazolyl) - acetamido/ - 3 acetoxymethylceph - 3 - em - 4 - carboxylic acid used at ths start of Example 4 was prepared as follows: 351 mg of 7 - /2 - (2 - tritylann'no - 4 - thiazolyl) - acetamido./ 3 - acetoxymethylceph - 3 - em - 4 - carboxylic acid, 0.44 cm of acetic acid and 0.22 cm of water were mixed; the mixture was warmed at 60°C, agitated for forty minutes, cooled, diluted with acetone then ether, and vacuum-filtered. The residue was dried to give 171 mg of the expected crude product.

This product was purified by taking up 470 mg of it in 5 cm of 1:1 ethanol:water solution close to its boiling point, vacuumfiltering the insoluble matter (A), then cooling the filtrate and vacuum-filtering the newly formed insoluble matter to isolate a first yield of 170 mg. The operation is then repeated using the insoluble matter (A) in place of the crude product and the filtrate of the first yield in place of ethanol-water solution. A second yield of 107 mg is obtained giving a total of 277 mg of the expected product.

The (2 - oxo - (3H) - thiazolin - 4 - yl)thiolocarboxylic acid used at the start of Example 4 was prepared as follows: 3 1.6 g of 70% sodium hydrosulphide, 16 cm of ethanol and 2.5 cm - 17 of ivater were mixed together at 10°C; 1.635 g of (2-oxo (3H) - thiazolin 4 - yl/carboxylic acid chloride were further added; the mixture was agitated for one hour, then the ethanol was driven off, water added, and 0.8 cm of concentrated hydrochloric acid were introduced with agitation. The product that crystallised out was separated by vacuumfiltration, rinsed and dried to give 1.46 g of the desired product.

Example 5 - /7^(2 - amino - 4 - thiazolyl) - acetamido/ - 3 - //(.2 - furyl) carbonyl) - thiomethyl/ - ceph - 3 - em - 4 - carboxylic acid. 0,25 g of 2 - furylthioloacetic acid, 4 cm of distilled water, 0.17 mg of sodium bicarbonate and 0.435 mg of the sodium salt of 7 /7-(2- amino - 4 - thiazolyl) - acetamido7 - 3 - acetoxymethylceph3 - em - 4 - carboxylic acid were mixed together; the mixture was left to stand for 5 hours at 50°C, then cooled to ambient temperature and acidified with acetic acid to a pH of 3 to 4. The resulting precipitate was vacuum-filtered, then rinsed and dried to give 420 mg of crude product. The product was dissolved in an aqueous sodium carbonate solution, then passed through an ion exchange column, eluting with water followed by a solution of water mixed with 10# of isopropanoi.

The fractions containing the product were united, the solvents were evaporated away under vacuum, and the aqueous residue was acidified with acetic acid. 115 mg of the expected product were obtained.

Analysis:, Ο,θΗ^Ο^ Calculated: C# 45.0 H# 3.4 ffill.7 S# 20.0 Found: C# 44.5 H# 3.5 N# 12.2 S# 20.0 The sodium silt of 7 - /7 - (2 - amino - 4 - thiazolyl) acetamido/ - 3 - acetoxymethylceph - 3 - em - 4 - carboxylic acid, used at the start of Example 5, was prepared as follows: - 18 4485γ 2.26 g of 7 - /7 - (2 - amino - 4 - thiazolyl)acetamido/ - 3 acetoxymethyl ceph - 3 - ein - 4 - carboxylic acid, 420 mg of sodium bicarbonate, 10 cm of water and 0.5 g of active charcoal were mixed together with agitation for three minutes at 50°C; the mixture was vacuum-filtered, washed with acetone and concentrated to 5 ml. 50 cm of acetone were added and the solution was heated to 60°C; the formed precipitate was separated by vacuum-filtration to give 1.745 g of the desired salt. (α)θ=+120° (c=l% in water).

Example 6 7-/7-(2- amino - 4 - thiazolyl )acetamido7 - 3 - propionyl thiomethyl ceph - 3 - em - 4 - carboxylic acid. a) Sodium thiolopropionate: 4.6 cm of propionyl chloride were introduced into a solution of sodium hydrosulphide prepared by dissolving 8 g of sodium hydrosulphide 3 in 20 cm of water then adding 128 cm of ethanol.

The mixture was allowed to react for 30 minutes before being vacuum-filtered and concentrated; the residue was taken up with ethanol, reconcentrated, then taken up once more with ethanol, vacuum-filtered and concentrated to dryness; ether was added to the residue, and 4.5 g of the expected product were recovered by vacuum-filtration. b) A mixture of 1.23 g of 7 - /7 - (2 - amino - 4 - thiazolyl) acetamido/ - 3 - acetoxymethylceph - 3 - em - 4 - carboxylic acid in cm of water containing 252 mg of sodium bicarbonate and 516 mg of sodium thiolopropionate was warmed at 60°G for 4 hours, 0.2 g of carbon black were added to the cool mixture, which was vacuum-filtered, acidified, washed and dried to give 0.88 g of the crude product.

A mixture containing 0.44 g of the crude product in 8.6 cm o of methylene chloride and 0.2 cm of triethylamine was agitated; the - 19 insoluble matter was vacuum-filtered and re-extracted. After another vacuum-filtration, the organic solutions were reunited and 3 concentrated; the residue was dissolved in water and 0.2 cm of acetic acid were added. The formed precipitate was separated by vacuum-filtration and washed and dried to give 0.232 g of the purified product. ^sis: C16H1805N4S3 Calculated: C% 43.42 HS2 4.1 ffi 12.56 SS! 21.73 Found: C2 43.3 IB 4.3 IK 12.2 SiS 20.8 Example 7 A preparation for injection was made up to the following formula: -/7 -(2- amino - 4 -thiazolyl)acetamido7 - 3 - acetyl thi omethyl ceph -3-em-4carboxylic acid 500 mg Sterile aqueous excipient q.s.v. . 5 cm Example 8 Gelatin capsules were prepared corresponding to the formula: 7-/7 - (2 - amino - 4 - thiazolyl)acetamido7 - 3 - acetyl thi omethyl ceph -3-em -4carboxylic acid 250 mg Excipient q.s. for one gelatin capsule up to 400 mg

Claims

1. 7 - aminothiazolylacetamido - cephalosporanic acid derivatives of the general formula: wherein R represents either a hydrogen atom or a group removable by 5 acid hydrolysis or by hydrogenolysis; R-| represents either an alkyl radical having 1 to 4 carbon atoms or a 5 membered heterocycle optianally containing a carbonyl group as one of its members; and A represents a hydrogen atom, an alkali metal atom, a substituted ammonium group, an equivalent of an alkaline-earth metal atom or an 10 equivalent of a magnesium atom.

2. A cephalosporanic acid derivative as claimed in claim 1, wherein A represents a sodium, potassium or lithium atom, or an equivalent of a calcium or magnesium atom, or a substituted ammonium group derived from trimethylamine, triethylamine, methylamine, propylamine, N,N 15 dimethylethanolamine or tris - (hydroxymethyl)-methylamine.

3. A cephalosporanic acid derivative as claimed in claim 1 or claim 2, wherein R represents at - butoxycarbonyl, trityl, di benzyl, trichloroethyl or carbobenzyloxy group.

4. A cephalosporanic acid derivative as claimed in claim 1, - 21 4 48 57 wherein R represents a hydrogen atom or a trityl grouo, R, represents a methyl, ethyl, furyl or 'i - oxo - (3H) - thiazolin - 4 - yl radical, and A represents a hydrogen atom.

5. , 7-/2-(2- Amino - 4 - thiazolyl) - acetamido/- 3 .5 (acetylthiomathyl) - ceph - 3 - em - 4 - carboxylic acid.

6. A process for preparing certain compounds of general formula I as defined in claim 1, in which an appropriate compound of general formula: 10 wherein R^ is as defined in claim 1, is treated with an appropriate acid of general formula: R \ '\h 9 — C —OH § (HI) or with a functional derivative thereof (wherein R' represents a group removable by acid hydrolysis or by hydrogenolysis) to obtain the 15 desired product of.general formula; - 22 4483 7 :h 2 — c — o CHg— S— C — R. C0 2 H II (Ia) wherein R' is as defined above and R-j is as defined in claim 1.

7. A process according to claim 6, in which the functional derivative of the acid of general formula III is the acid chloride 5 or an acid anhydride.

8. A process according to claim 7, in which the acid anhydride is formed in situ by the action of isobutyl chloroformate on the acid of general formula III.

9. A process according to claim 6, in which the functional 10. Derivative of the acid of general formula III is an acid halide, or an acid anhydride formed by the action of isobutyl chloroformate, which process is carried out in the presence of a base.

10. A process according to claim 9, in which the base is an alkali metal carbonate, N - methyl - morpholine, pyridien, or triethylamine. 15

11. A process according to any of claims 6 to 10, in which the compound of general formula II is in turn prepared by treating an appropriate compound of general formula: R,-C-S-B (IV) - 23 (wherein is as defined in claim 1 and 8 reorew-i ? an alkali me^al atom or hydrogen atom) with 7 - amino - cephalosporanic acid.

12. A process for preparing a compound of general formula la as defined in claim 6, substantially as described herein with reference 5 tb Example 3,

13. A compound of general formula la when prepared by a process as claimed in any of claims 6 to 12.

14. A process for preparing cetain compounds of general formula I as defined in claim 1, in which an appropriate compound of general 10 formula la as defined in claim 6 is hydrolysed in an acidic medium, or hydrogenated, to form the corresponding product of general formula wherein R-j is as defined in claim 1.

15. A process as claimed in claim 14, in which R' in general formula la is a t - butoxycarbonyl or trityl group and the reaction is performed 15 by hydrolysis in an acidic medium.

16. A process as claimed in claim 15, in which the acid employed is trifluoroacetic acid, formic acid or acetic acid,

17. A process as claimed in claim 14, in which R 1 in general formula la is a tri chloroethyl group and the reaction is performed by hydro20 genolysis employing a hydrogenating agent. --24* 48S 111. Λ process as claimed in ι laim 1/, in which tlie hydruijenating agent is a zinc/acetic acid system.

18. 19. A process as claimed in claim 14, in which R' in general formula la is a benzyl, dibenzyl or carbobenzyloxy group and the 5 reaction is performed by catalytic hydrogenation.

19. 20. A process as claimed in any of claims 14 to 19, in which the appropriate compound of formula la is prepared by a process claimed in any of claims 6 to 12.

20. 21. A process for preparing the compounds of general formula Ib as 10 defined in claim 14, substantially as described herein with reference to Example 2,

21. 22. A compound of general formula Ib when prepared by a process as claimed in any of claims 14 to 21.

22. 23. A process for preparing certain compounds of general formula 15 I as shown in claim 1, in which an appropriate compound of general formula: (wherein R is as defined in claim 1 and A' represents a hydrogen atom or an alkali metal atom) is treated with an appropriate compound of 20 general formula IV as defined in claim 11 to give the corresponding compound of general formula I wherein A represents a group A'. - 25 «4857

23. 24. A process as claimed in claim 23, in which the reaction is performed in water, or in a water/acetone mixture.

24. 25. A process as claimed in claim 23 or claim 24, in which the reaction is performed in the presence of a buffer that maintains 5 the pH of the reaction medium close to neutrality.

25. 26. A process as claimed in claim 25, in which the buffer is a monosodium phosphate/sodiutn acid carbonate buffer.

26. 27. A process as claimed in any of claims 23 to 26, in which each . of B and A 1 in the compounds of general formulae IV and V respectively 10 represents an alkali metal •atom.

27. 28. A process as claimed in claim 27, in which the alkali metal atom is sodium or potassium.

28. 29. A process as claimed in claim 27 or claim 28, in which the compound of general formula IV wherein B represents an alkali metal 15 atom and the compound of general formula V wherein A' represents an alkali metal atom are prepared in situ by salifying corresponding compounds of general formula IV and V in which B and A' respectively represent a hydrogen atom.

29. 30. A process for preparing the compounds of general formula I, 20 as defined in claim 1, wherein A represents a hydrogen atom, in which process a compound of general formula I wherein A represents an alkali metal atom is treatment with an acid to give the desired product.

30. 31. A process as claimed in claim 30, in which the acid is acetic acid. 25

31. 32. A process as claimed in claim 30 or claim 31, in which the compounds of general formula I wherein A represents an alkali metal atom are prepared by a process as claimed in any of the claims 27 to 29.

32. 33. A process for preparing compounds of general formula I, as - 25 4 4857 defined in claim 1, wherein A represents A 1 (as defined in claim 23), substantially as described herein with reference to any one of Examples 1, 4, 5 and 6.

33. 34. A compound of general formula I wherein A represents A 1 (as defined in claim 23) when prepared by a process as claimed in any of claims 23 to 33.

34. 35. A process for preparing the compounds of general formula I, as defined in claim 1, wherein A represents an alkali metal atom, an equivalent of an alkaline-earth metal atom or of magnesium, or a quaternary ammonium group, in which the corresponding compound of general formula I wherein A represents a hydrogen atom is treated with a suitable base to form the desired product.

35. 36. A process as claimed in claim 35, in which the base employed is a carbonate or hydroxide of said metal atom or an appropriate amine.

36. 37. A process as claimed in claim 35 or 36, in which the reaction is performed in a solvent comprising one or more of water, ethyl ether, ethanol and acetone.

37. 38. A process as claimed in any of claims 35 to 37, in which the compound of general formula I wherein A represents a hydrogen atom is prepared by a process as claimed in any of claims 5 to 12, 14 to 21, 23 to 26, or 30 to 33.

38. 39. A compound of general formula I, wherein A represents an alkali metal atom, an equivalent of an alkaline-earth metal atom or of magnesium, or a quaternary ammonium group, when prepared by a process claimed in any of claims 35 to 38.

39.

40. Pharmaceutical compositions containing as active ingredient one or more compounds of general formula I, as defined in claim 1, in association with a suitable pharmaceutical vehicle.

41. A composition as claimed in claim 40, in which the , phawna'cewticM veM'clp.'aSfcMws esv or te#

42. A pharmaceutical composition as claimed in claim 40 or claim 41 in which the active ingredient is or includes a compound of general formula I as defined in claim 3,

43. A pharmaceutical composition as claimed in claim 40 or claim 10 41, in which the active ingredient is or includes a compound of general formula I as defined in claim 4.

44. A pharmaceutical composition as claimed in claim 40 or claim 41, in which the active ingredient is or includes 7-/7-(2- amino 4 - thiazolyl) - acetamido/ - 3 (acetylthiomethyl) - ceph - 3 - em 15 4 - carboxylic acid.

45. A pharmaceutical composition as described herein with reference to Example 7 or Example 8.